We plan to study the mechanism of RNA synthesis by vesicular stomatitis virus. Various phosphorylated forms of the NS protein will be purified and assayed in in vitro transcription systems to determine whether the different forms carry out different functions. The different forms of NS will be assayed for ability to carry out RNA synthesis and the products will be characterized as to size and modifications (capping, methylation, polyadenylation). The different NS forms will also be tested for ability to bind to template and interact with L protein. Kinetic assays will be carried out on the polymerases from wild type and defective interfering particles and their interactions with the respective templates characterized.